/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *  (C) 2006 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include "mpitest.h"

/*
static char MTEST_Descrip[] = "Test of a large number of derived-datatype messages eagerly, with no preposted receive so that an MPI implementation may have to queue up messages on the sending side";
*/

#define MAX_MSGS 30

int main( int argc, char *argv[] )
{
    int errs = 0;
    int rank, size, dest, source;
    int i, indices[40];
    MPI_Aint extent;
    int *buf, *bufs[MAX_MSGS];
    MPI_Comm      comm;
    MPI_Datatype  dtype;
    MPI_Request   req[MAX_MSGS];

    MTest_Init( &argc, &argv );

    comm = MPI_COMM_WORLD;
    MPI_Comm_rank( comm, &rank );
    MPI_Comm_size( comm, &size );
    source = 0;
    dest   = size - 1;
    
    /* Setup by creating a blocked datatype that is likely to be processed
       in a piecemeal fashion */
    for (i=0; i<30; i++) {
	indices[i] = i*40;
    }

    /* 30 blocks of size 10 */
    MPI_Type_create_indexed_block( 30, 10, indices, MPI_INT, &dtype );
    MPI_Type_commit( &dtype );
    
    /* Create the corresponding message buffers */
    MPI_Type_extent( dtype, &extent );
    for (i=0; i<MAX_MSGS; i++) {
	bufs[i] = (int *)malloc( extent );
	if (!bufs[i]) {
	    fprintf( stderr, "Unable to allocate buffer %d of size %ld\n", 
		    	i, (long)extent );
	    MPI_Abort( MPI_COMM_WORLD, 1 );
	}
    }
    buf = (int *)malloc( 10 * 30 * sizeof(int) );
    
    MPI_Barrier( MPI_COMM_WORLD );
    if (rank == dest) {
	MTestSleep( 2 );
	for (i=0; i<MAX_MSGS; i++) {
	    MPI_Recv( buf, 10*30, MPI_INT, source, i, comm, 
		      MPI_STATUS_IGNORE );
	}
    }
    else if (rank == source ) {
	for (i=0; i<MAX_MSGS; i++) {
	    MPI_Isend( bufs[i], 1, dtype, dest, i, comm, &req[i] );
	}
	MPI_Waitall( MAX_MSGS, req, MPI_STATUSES_IGNORE );
    }

    MPI_Type_free( &dtype );
    MTest_Finalize( errs );
    MPI_Finalize();
    return 0;
}
